There may be times when you need to express breast milk for your baby, e.g. if you are going out or returning to work; or if your baby is preterm or unwell and unable to breastfeed. The principle behind expressing breast milk is to copy as closely as possible what occurs with normal breastfeeding. Frequent and thorough removal of milk from the breasts is very important for milk production. Expressing by hand or using an electric pump needs to commence as soon as possible after the birth of your baby.